The Hobbit: The Battle of the Five Armies will end with a 45-minute battle sequence, Digital Spy said.

Director Peter Jackson shared his plans for the extended fight scene with Entertainment Weekly, and revealed that there's a plan in place to stop the audience suffering from "battle fatigue".

Jackson said: "We have a rule that we're not allowed more than two or three shots of anonymous people fighting without cutting back to our principal characters. Otherwise the audience just ends up with battle fatigue."

The director also shared that the large-scale battle, which will take place at the bottom of the Lonely Mountain, required a lot of forward planning.

He said: "We had to design the landscape itself and figure out, 'OK, if we have 10,000 orcs, how much room are they going to take up?'

"'Are they going to fill up the valley or look like a speck?' Then we could start drawing the arrows on the schematics."

Jackson confirmed that eagles will play a role in the 45-minute battle finale, but not in the typical save-the-day fashion fans have come to expect.

"Tolkien uses eagles in a way that can be kind of awkward because they tend to show up out of the blue and change things pretty quickly," he said.

"So here they're just part of the plan, not the saviours. I mean, I do realise that if the eagles had just been able to bring Frodo to Mount Doom in Lord of the Rings and let him drop the ring in, those movies would have been much shorter."

The Hobbit: The Battle of the Five Armies will be released on December 12 in the UK and on December 17 in the US.